Fabrication of Superior Single-Atom Catalysts toward Diverse Electrochemical Reactions

Single metal atom catalysts on supports have become a new frontier in the field of catalysts, which possess the maximum atomic utilization efficiency and have an unsaturated coordination environment. With their unique electronic and structural properties, single metal atoms usually show distinctive catalytic performance toward various chemical reactions. It is challenging, however, to synthesize stable single metal atom catalysts because of their high surface energy and tendency toward aggregation. Herein, recently reported advanced preparation methods for single metal atoms, with a particular focus on how to stabilize these single metal atoms against migration and aggregation, are summarized. In addition, the electrochemical conversion and storage applications of single metal atoms are discussed in detail with a special emphasis on the oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction, and carbon dioxide reduction reaction, as well as on their use in batteries. Finally, the current challenges and opportunities for the development of this field are addressed.